Saying the measure of “operational control” of U.S. borders is obsolete, Homeland Security Secretary Janet Napolitano told Congress on Wednesday that the Obama administration is trying to come up with a new yardstick to better reflect the improvements it says it has made.

With the Government Accountability Office, Congress’s chief watchdog, saying less than half of the southern border is under operational control, the Obama administration has been distancing itself from that measure for more than a year.

” ‘Operational control’ it’s an archaic term,” Miss Napolitano told the Senate Homeland Security Committee. “The fact of the matter is that we need a more quantitative and qualitative way to reflect what actually is occurring at the border.”

The wording is more than just a semantic game.

House Republicans, in their campaign Pledge to America last year, set operational control as their goal, and at least some of the triggers lawmakers have suggested for determining when to move to legalization of illegal immigrants already here require the government first to prove it has control of the border.

Congress itself defined operational control in a 2006 law as the ability to prevent all unlawful entries into the United States, but all sides now say that amounts to sealing the border, which they say is impossible.

“Everybody seems to agree it’s not feasible to achieve operational control as it’s defined there,” said committee Chairman Joe Lieberman, Connecticut independent. “Either we have to come up with another definition or we have to set some sort of standards for getting closer to operational control.”

On Wednesday, Miss Napolitano said she has asked U.S. Customs and Border Protection to come up with another way to measure the true state of security along the border.

She said she wants to try to include measures of how many people have been deterred from even trying to cross in the first place, as well as stats that would show the increasingly violent clashes and collateral damage fueled by the drug trade.

Border Patrol officials in Washington have said operational control doesn’t capture the true state of the border because there are places where natural boundaries make crossings so rare that there’s no need to have the kind of manpower and technology needed in other places.

Still, the other chief measure of border security - the number of illegal immigrants apprehended while trying to cross - has its own problems.

The GAO and local U.S. Border Patrol offices regularly use the term “operational control,” and define it to mean Border Patrol agents have the ability to deter, detect and respond to illegal crossers.

In February, the GAO said that the U.S. had operational control along 873 miles of the 2,000-mile border. Of those miles, just 15 percent were designated as “controlled,” while the rest were designated a slightly lesser category of “managed.”

On the more expansive northern border, the GAO says the picture is even more grim: just 32 of the border’s 4,000 miles are under operational control.

Sen. John McCain, a frequent opponent of Miss Napolitano on the issue, said the issue isn’t the yardstick, it’s the fact that many people living on the border feel unsafe.

“If you want to change the metrics, change the metrics, but on the ground in Arizona, on the border, we see people still living in an environment where they’re not secure lives,” the Arizona Republican said.

He said voters will not accept a plan to legalize illegal immigrants until the government proves it can police the border more effectively.

Miss Napolitano, though, said the border cannot be secured unless the rest of immigration is also addressed.

“There’s a linkage between immigration reform and the border,” she said. “If you deal with the legal immigration system, that also has an impact on what is in the illegal immigration system. And so this is a Gordian knot that we must untie, looking at all of these things together.”